海拉尔盆地贝尔凹陷伸展断层转折褶皱作用及其对沉积作用的制约  

Extensional Fault-Bend Folding and Its Constrains on the Sedimentation of Beier Sag in Hailar Basin

作　　者：刘志宏[1] 梅梅[1] 柳行军 吴相梅[3] 万传彪[3] 林东成[3] 高军义[3] 

机构地区：[1]吉林大学地球科学学院,长春130061 [2]东方地球物理勘探有限责任公司,河北涿州072751 [3]大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712

出　　处：《吉林大学学报（地球科学版）》2012年第5期1330-1337,共8页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41072150)

摘　　要：海拉尔盆地是叠置于内蒙—大兴安岭古生代碰撞造山带之上的中新生代盆地,总体上呈北东向展布,由3坳、2隆5个一级构造单元组成,自西向东依次为扎贲诺尔坳陷、嵯岗隆起、贝尔湖坳陷、巴彦山隆起和呼和湖坳陷,其中贝尔凹陷是贝尔湖坳陷南部的1个二级构造单元。贝尔凹陷的控陷断层为1个上凸、2个上凹断层转折组合构成的犁式正断层,在深部发育伸展双重构造。在犁式正断层上盘由于上凸断层转折产生的活动轴面与断层面为同旋向剪切,而上凹断层转折产生的活动轴面与断层面为反旋向剪切,在断层上盘形成2个背斜中间夹1个向斜的构造组合。由活动轴面与固定轴面之间滚动面的宽度确定控陷断层F1在早白垩世南屯期晚期的水平伸展量为6 850m。贝尔坳陷伸展断层转折褶皱的几何学和运动学特征,反映了断层滑移速率、构造沉降速率和沉积速率对凹陷内沉积地层变形特征的影响和构造活动对沉积作用和油气地质条件的制约。贝尔凹陷南屯组上段内部角度不整合的形成与变形作用中的剥蚀作用和沉积间断无关,而是由于半地堑从略欠补偿充填向过补偿充填状态转变时,沉积速率相对于构造沉降速率显著增加所致。Hailar basin is a Meso-Cenozoic basin which superimposed on the Inner Mongolia-Greater Hinggan Mountain Paleozoic collision orogenic belt.The basin,trending north-east,is consist of five first-order structural units（three depressions and two uplifts）,from west to east are Zhalenuoer depression,Cuogang uplift,Beier Lake depression,Bayanshan uplift and Huhe Lake depression.Beier sag is a second-order structural unit in the south of Beier Lake depression.The control subsidence fault of Beier sag is a listric normal fault which consists of a convex and two concave fault-bend,and formed extensional duplex in depth.The shear rotation of active axial surface caused by convex fault-bend is the same as the fault plane,the shear rotation of active axial surface caused by concave fault-bend is contrary to the fault plane,and two anticline sandwiching a syncline formed in hanging wall of listric normal fault.The horizontal extension of the control subsidence fault F1 is 6 850 m during Late Nantun Period in the Early Cretaceous,determined by the rollover width between active axial surface and inactive axial surface.The geometry and kinematics of extensional fault-bend fold in Beier sag reflect the impact of the fault slip rate,the tectonic subsidence rate,deposition rate on deformation characteristics of sedimentary strata and constrains on the sedimentation and petroleum geological conditions in the depression.The internal angular unconformity of the Upper Member of Nantun Formation in Beier sag developed without erosion or hiatus on deformation due to increases in deposition rate relative to subsidence rate,where half-graben compartments change from sediment-underfilled to overfilled conditions.

关 键 词：伸展构造 断层转折褶皱作用 生长地层 沉积作用 角度不整合 贝尔凹陷 海拉尔盆地 

分 类 号：P54[天文地球—构造地质学] P618.13[天文地球—地质学]